The present invention relates to a network connection type storage, a server system and an operating system.
When providing a service using the Internet, companies may use a service provided by a data center to reduce Internet connecting equipment and the cost of building a computer system.
The data center has Internet connecting equipment and rents out server installation space and servers of companies (customers) which desire to provide a service using the Internet. Generally, independent storages rented out to the customers are often allocated to hold security between the customers.
However, in the method for allocating independent storages to customers, it is difficult to change the storage volume flexibly rented out according to change in demand of the customers. All storages must be monitored for failure. The managing cost is higher due to increase in the number of storages.
Logically divided bulk storages are logical volumes. Customer servers and the bulk storages are connected by the SAN (Storage Area Network). Managing the storages can be concentrated to reduce the managing cost. However, a fiber channel interface which is currently dominant in the SAN is expensive. Customers make an agreement by a money amount according to installation space. There is no enough space for adding the interface to the customer servers.
The NAS (Network Attached Storage) uses the NFS service and the CIFS service so that a file system incorporated into the NAS or generated on a storage connected via a storage interface such as SCSI and a fiber channel can store a file into other information processors and share it via a network. The NAS can release a file system below the specified directory and can be set to release plural directories.
For Internet connection, in the data center, almost all customer servers have a network interface. The NAS can provide a storage service to plural customers without adding hardware to the customer servers. The NAS often uses a general-purpose OS (operating system) and may suffer from damages caused by hacking of a malicious user and file tampering and file deletion due to virus. When the plural customers share the NAS, these damages may affect all the customers sharing the same NAS.
The NAS of Network Appliance has MultiStore (“Data ONTAP 6.2 MultiStore Administration Guide”). This can provide plural virtual servers called vfiler such as the CIFS service and the NFS service having one or more IP addresses and volumes on one system. The vfiler is allocated to each customer, permitting user management and independent setting for each customer.
The vfiler allows the customer to execute a command using the rsh protocol. The setting of the NFS service can be changed. A back-up device connected to the NAS cannot be used. To use the back-up device connected to the NAS, a system managing the entire system must be used.
A system using virtual computers to allocate an independent OS to each customer for providing a service is disclosed in Japanese Patent Application Laid-Open No. 2002-024192. In the technique described in Japanese Patent Application Laid-Open No. 2002-024192, plural OSes are operated on one computer to allocate an independent resource, that is, a main storage and a network adapter to each of the OSes. Since the resource is not shared between the OSes, user management and independent setting for each customer can be made easily. Further, the system can be used for back-up by allocating the resource of a back-up device.